Tips for healthy diet during cancer treatment with radiation therapy


Radiation therapy is an effective cancer treatment method, but it also greatly affects the patient’s health due to the side effects accompanied. Therefore, after radiotherapy, the patient’s menu requires adequate nutrients to improve and maintain the best health. Below are tips for healthy diet during cancer treatment with radiation therapy for your reference.

How does radiation therapy affect your diet?

Radiation therapy greatly affects the patient’s health (Pic: Freepik)

Most patients during cancer treatment experience loss of appetite, nausea, vomiting, etc., leading to poor absorption of nutrients, that results in body weakness over time… However, the extent to which radiation therapy affects eating depends on many factors such as radiation dose, location and size of the irradiated area.

Radiation rays such as X-rays, Gamma rays, etc. possess extreme penetrating and destructive properties. In the process of destroying cancer cells, they will more or less damage healthy cell areas and adversely affect the patient’s digestive system. Some specific digestive symptoms that you may face during radiotherapy include:

  • Impact on the digestive system: Radiation therapy may cause side effects such as fatigue, nausea, vomiting, diarrhea or constipation. These effects can affect your ability to digest and absorb nutrients from food. Patients may feel uncomfortable or loose appetite when experiencing these problems.
  • Changes in taste and smell: Some patients may experience changes in taste or smell after radiotherapy. This can change their appetite and affect their food preferences or ability to tolerate certain foods.
  • Psychological impact: Radiation therapy can cause stress and anxiety in patients and this can affect their attitude towards eating. Some people may become unwilling to eat or lose their appetite due to psychological reasons.
  • Impact on overall health: Radiation therapy is possible to cause side effects such as dehydration, fatigue, and unwanted weight loss or weight gain. These impact can affect the patient’s overall health and influence nutritional needs and calorie intake.

Due to the above effects, managing the patient’s diet during radiotherapy becomes more important than ever. Nutrition experts recommend that patients maintain a healthy diet and provide adequate nutrition throughout treatment.

Healthy nutrition for people undergoing radiotherapy

Maintaining a healthy diet is important for people undergoing radiation therapy, for the reason that it helps their bodies recover quickly and better withstand the effects of therapy. Below are some basic nutritional tips for people undergoing radiation therapy:

Provides adequate calories for the body 

Radiation therapy drains significant energy from patients, putting many at risk of unintentional weight loss. Consuming more energy ensures that patients have enough energy needed to maintain daily activities and support the recovery process, avoiding malnutrition, weight loss and exhaustion. According to recommendations, people undergoing radiotherapy should absorb about 25 – 40 kcal/kg of body weight per day. Thus, a sick person with a weight of about 60 kg needs to get enough daily energy of about 1500 – 2400 kcal.

During radiotherapy, it is necessary to supplement a healthy diet to help patients recover quickly (Pic: Freepik)

Increase protein

According to recommendations of the American Cancer Society, providing enough daily protein for people undergoing radiation therapy is very important. Protein helps recovery after radiotherapy and minimizes side effects of treatment. To ensure adequate protein intake, radiotherapy recipients can integrate protein sources into their diet including meat, fish, eggs, beans, nuts, milk and dairy products. In addition, protein supplements can be used if necessary under the guidance of a doctor or nutritionist. The amount of protein needed can range from 45 to 60g per day, depending on each person’s weight and specific needs.

Enhance vitamins and minerals

To support the overall health and recovery process of people undergoing radiotherapy, patients should absorb enough vitamins and minerals from their daily menu, including:

  • Vitamin A: Supports development and protects eyes, skin, and immune system. Radiation therapists can get it from foods like carrots, pumpkin, mustard greens, and fruits like watermelon and tomatoes.
  • Vitamin B: Includes many types such as B1, B2, B3, B6, B9 (folic acid), and B12, which are all important for energy metabolism and cell growth. Sources include meat, fish, eggs, whole grains, green vegetables, and dairy products.
  • Vitamin C: Supports the immune system and wound healing process. Sources include oranges, grapefruits, strawberries, tomatoes, and collard greens.
  • Vitamin D: Supports calcium absorption and bone development. Good sources include salmon, eggs, milk and dairy products, as well as sunshine.
  • Vitamin E: An antioxidant helps protect cells from damage. Provided from seeds, barley seed oil, almonds and mustard greens.
  • Minerals: Some important minerals for people undergoing radiation therapy include calcium, magnesium, zinc and iron. Calcium helps maintain bone health, magnesium supports muscle and nerve function, zinc strengthens the immune system and iron provides oxygen to the body. Absorbing these minerals sufficiently allows patients to stay healthy and resist the side effects of radiotherapy.

Prioritize soft, easy-to-digest foods

People undergoing radiotherapy should prioritize soft, easy-to-digest foods (Pic: Freepik)

Some side effects of radiotherapy (nausea, vomiting, difficulty swallowing, bloating, etc.) can make the digestive system more sensitive and weak. At this time, in order for the digestive process to proceed smoothly, patients should prioritize soft, easy-to-digest foods such as: pureed soup, porridge, vermicelli, pho,… or soft ripe fruits such as mango, banana, papaya,…

Foods to avoid for patients undergoing cancer radiotherapy?

People undergoing radiotherapy for cancer need to pay attention to their diet to support the recovery process and reduce side effects of treatment. Below are some foods and types of food should be limited or avoided while undergoing treatment:

Foods to avoid for patients undergoing radiotherapy (Pic: Freepik)

  • Foods with strong smell: People undergoing radiotherapy are extremely sensitive to the smell and taste of food. Smelling and coming into contact with them make the patient feel loss of appetite, discomfort and lead to vomiting. Therefore, during radiotherapy, preparing food gently and ventilating the eating space can also help reduce the impact of smell on them.
  • Dry, hard foods: Upon receiving radiation therapy to the neck, head or chest area, patients often have difficulty swallowing and may experience dry mouth. Dry and hard foods can increase difficulty in swallowing and consuming nutrients, causing loss of appetite and causing additional negative effects to the treatment process. Instead, people undergoing radiation therapy should prioritize dishes that are easy to eat and digest such as: vermicelli, noodle, pho, soup, and porridge, etc.
  • Foods containing stimulants: During radiotherapy and cancer treatment in general, patients need to completely eliminate foods containing alcohol and stimulants. Since this is the leading factor that worsens your medical condition. Specifically, alcohol or ethanol in beer has the ability to decompose into acetaldehyde – a compound that damages DNA and prevents cells from recovering. Therefore, for the radiotherapy process to be effective, alcohol and stimulants should be absolutely avoided.
  • Canned foods: Canned foods often have low nutritional value and often contain many preservatives and spices that can be harmful to health, especially for people undergoing radiotherapy. Large oil content in canned products can also increase the feeling of indigestion and bloating, affecting the patient’s health. Therefore, the menu for people undergoing radiotherapy should prioritize fresh foods and consuming within day.
  • Spicy foods: Spicy foods is able to irritate the stomach and increase discomfort, especially when the digestive system is sensitive. This can worsen the effects of radiotherapy on the digestive system, causing the patient to feel uncomfortable and lose appetite, …

What to eat to minimize side effects of radiation therapy

To minimize side effects of radiotherapy, patients can take some measures in their diet. Here are some tips on foods and eating strategies that could reduce the side effects of radiation therapy.

Side effects Diet


Vomiting, nausea


 Try a liquid diet such as milk, fruit juice, porridge, bread, gelatin foods.

  Food should be served after cooling down, avoid food that is too hot or too cold.

  Avoid spicy foods, fried foods and sweet foods.

  Drink sips of ginger water, lemonade or eat mint candy or ginger candy.



  Supplement adequate fluids: drink 8-12 cups/day (cups of water/ diluted tea/ fruit juice).

  Supplement electrolytes with foods rich in sodium and potassium such as bananas, oranges, peaches, apricot juice, boiled/mashed potatoes.

  Food should be limited:

+ Alcoholic beverages, beer, wine, coffee, black tea, soda, chocolate.

+ Gas-producing foods and drinks such as cabbage, broccoli, soy milk and other soy products.

+ Spicy foods: hot sauce, curry, chili,…

+ Fried foods, greasy foods, fast foods.

+ Foods high in insoluble fiber such as raw vegetables, fruits, nuts and whole grains.






 Drink enough filtered water/fruit juice: 40 ml/kg/day (Patients who vomit or urinate a lot or sweat a lot need to increase 300-500ml/day)

 Increase foods high in fiber such as: fresh vegetables, fresh fruits, whole grains, beans and nuts.

 Add intestinal probiotics such as yogurt and liquid yogurt.


Difficulty swallowing


 Choose foods and drinks that are high in energy and high in protein such as milk, soup, meat, etc.

 Choose soft, wet foods that are easy to swallow such as simmered cereal, mashed potatoes, eggs mixed with milk, yogurt or sauce, broth, etc. while eating.

 Food should be limited

+ Hot and spicy food/drink

+ Acidic foods and drinks such as tomatoes, citrus, lemons, and grapes.

+ Crispy hard foods, such as fried cockroaches.

+ Tobacco and alcoholic beverages.

 Dry mouth, mouth ulcers

 Choose foods that are soft, slippery, and easy to swallow, such as simmered cereal, mashed potatoes, or stir-fried eggs with butter/milk.

 Take small pieces of rice, chew thoroughly and take additional sips of the fluid while eating.

 Eat warm foods or at room temperature.

Is it possible to take dietary supplements during radiotherapy?

The use of dietary supplements during radiotherapy should be carefully considered and advised by a doctor or nutritionist. They will provide an assessment of your specific nutritional needs and recommend appropriate supplements. Avoid using dietary supplements without your doctor’s guidance. Excessive or improper use may cause side effects and leave impact on the treatment process. In particular, dietary supplements should be chosen with quality products from reliable sources to ensure safety and effectiveness.

Menu for patients undergoing radiotherapy?

The menu before, during and after radiotherapy may varies to suit the nutritional needs and health status of the patient. Below are some suggestions for each stage:

Before radiotherapy

Before radiotherapy, maintaining a balanced and nutritious diet is essential to get the body ready before treatment process. Below are some suggestions for foods could be included in your diet before starting radiation therapy:

Maintain a healthy diet and supplement adequate nutrients before radiotherapy (Pic: Freepik)

  • Foods rich in protein: Protein is an important ingredient to support basic health and recovery after radiotherapy. Some good sources of protein include poultry (chicken, turkey), fish, seafood, eggs, beans, soybeans, nuts, milk and unsweetened dairy products.
  • Fruits and vegetables: Vegetables and fruits are rich in fiber and vitamins, which help provide energy and maintain a strong immune system. Include a variety of vegetables such as greens (spinach, cabbage), carrots, tomatoes, pumpkin, eggplant, celery, watercress, tomatoes, and fresh fruits.
  • Whole grains: Whole grains provide lasting energy and are an important source of nutrients. Whole grains include oats, barley, brown rice, chia seeds, corn kernels, and quinoa.
  • Foods rich in calcium: Calcium is an important mineral for bone and tooth health, especially during recovery from radiotherapy. Some sources of calcium could be milk, soy milk as well as calcium-rich green vegetables such as spinach, moringa, spinach, coriander, and watercress.
  • Drinks: Make sure you get enough water every day to keep your body hydrated and aid recovery. Water, seltzer, unsweetened fruit juice, and unsweetened tea and coffee are good options.

During radiotherapy

  • The menu contains light food easy to digest: During radiotherapy, easy-to-digest food is important to reduce the impact on the digestive system and support the recovery process. This can be soup, porridge, fiber-rich foods such as green vegetables and fruits, soft and easily digestible fish meat.
  • Prioritize fresh fruits and vegetables in large quantity: This is a food group rich in vitamins, antioxidants, minerals, and fiber that are good for people undergoing radiotherapy for cancer. Cancer patients should eat a lot of carrots since it contains a great amount of β-carotene. This substance, after entering the body, will be converted into vitamin A – a vitamin participates in the process of killing cancer cells and help prevent changes in the remaining healthy cells in the body.
  • Drink enough water: Adequate amount water intake could speed up the process of removing radiotherapy drugs from the body. Patients can add more water to the body by drinking juice and eating liquid foods,…

At the same time, patients can supplement nutritional products for cancer patients to increase treatment effectiveness. Nutricare’s Leanmax Hope nutritional product for cancer patients is the optimal choice trusted by many experts and patients. Leanmax Hope is a specialized nutritional product for cancer patients that has been clinically proven. Adding 2 glasses of Leanmax Hope milk every day allows cancer patients to gain weight (average 1.4kg) and muscle (average 1.2kg) after 8 weeks. At the same time, the patient’s quality of life is also significantly improved such as reduced fatigue and pain; increased mobility; improve quality of life. Nutricare’s Leanmax Hope product has been recognized as a National Medical Nutrition Brand. Products for cancer patients and patients undergoing chemotherapy/radiation therapy. Adults and children over 3 years old who need high-energy nutritional supplements to restore health can also supplement Leanmax Hope in their daily diet.

 Maintaining a balanced and nutritious diet is important to help the body recover after radiation therapy (Pic: Freepik)

After radiotherapy

After radiotherapy, patients should take foods that are easy to digest and rich in nutrients. At this time, people undergoing radiotherapy for cancer may experience some unwanted side effects such as body aches, fatigue, loss of appetite, etc. Below are some suggested foods that should be on the menu for those after radiotherapy:

  • Foods rich in protein such as lean meat, eggs, fish, skim milk, etc.
  • Dark vegetables, tubers, and fruits such as carrots, broccoli, bell peppers, tomatoes, kohlrabi, etc.
  • Fresh coconut water: Regularly drinking fresh coconut water helps the body eliminate toxins and strengthen the immune system.
  • Whole grains such as barley, wheat, brown rice, oats, millet, etc.
  • However, each patient has different physical condition and medical condition. Therefore, nutritionist should be consulted to develop a menu for people undergoing radiotherapy for cancer.








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